Non-nutritive sucking habits, dental malocclusions, and facial morphology in Brazilian children: a longitudinal study.

The aim of this longitudinal study was to assess the relationship between non-nutritive sucking habits and the presence of anterior open bites (AOBs) and posterior crossbites and their association with facial morphology among 4- to 6-year-old children attending state schools in the city of Recife, Brazil. The sample comprised 287 children, both males and females. The proportion of boys to girls was approximately 50 per cent. The average age was 4 years 5 months at the beginning and 6 years 6 months at the end of the study. Data were collected from interviews with mothers or carers, and the clinical examination was carried out by two calibrated examiners. Statistical analysis was undertaken using bivariate analysis, Pearson's chi-square, McNemar, and Stuart-Maxwell tests. The results revealed a significant reduction in AOB (P < 0.001) and a slight increase in the prevalence of posterior crossbites. Both occlusal traits were associated with a previous history of sucking habits. The most prevalent morphological facial type, assessed using the morphological facial index, was high (> or =88 mm) and a statistically significant (P = 0.02) association was found between facial morphology and an AOB. Children with an average or high facial morphology measurement exhibited a greater prevalence of AOB when compared with those with lower measurements. Self-correction of AOB was associated with cessation of sucking habits but facial morphology remained unaltered.